Liodakis, IoannisKiehlmann, SebastianMarscher, Alan P.Zhang, HaochengBlinov, Dmitryet al2024-08-072024-08-072024-07-09Liodakis, Ioannis, Sebastian Kiehlmann, Alan P. Marscher, Haocheng Zhang, Dmitry Blinov, et al. “Testing Particle Acceleration in Blazar Jets with Continuous High-Cadence Optical Polarization Observations.” Astronomy & Astrophysics, July 9, 2024. https://doi.org/10.1051/0004-6361/202451037.https://doi.org/10.1051/0004-6361/202451037http://hdl.handle.net/11603/35184Authors- Ioannis Liodakis, Sebastian Kiehlmann, Alan P. Marscher, Haocheng Zhang, Dmitry Blinov, Svetlana G. Jorstad, Iván Agudo, Erika Benítez, Andrei Berdyugin, Giacomo Bonnoli, Carolina Casadio, Chien-Ting Chen, Wen-Ping Chen,Steven R. Ehlert, Juan Escudero, Tatiana S. Grishina, David Hiriart, Angela Hsu,Ryo Imazawa, Helen E. Jermak, Jincen Jose, Philip Kaaret, Evgenia N. Kopatskaya, Bhavana Lalchand,Elena G. Larionova, Elina Lindfors, José M. López, Callum McCall, Daria A. Morozova, Efthymios Palaiologou, Shivangi Pandey, Juri Poutanen, Suvendu Rakshit, Pablo Reig, Mahito Sasada, Sergey S. Savchenko, Elena Shablovinskaya, Sharma Neha, Manisha Shrestha, Iain A. Steele, Ivan S. Troitskiy, Yulia V. Troitskaya, Makoto Uemura, Andrey A. Vasilyev, Zachary Weaver, Klaas Wiersema, Martin C. WeisskopfVariability can be the pathway to understanding the physical processes in astrophysical jets. However, the high-cadence observations required to test particle acceleration models are still missing. Here we report on the first attempt to produce continuous, > 24 hour polarization light curves of blazars using telescopes distributed across the globe, following the rotation of the Earth, to avoid the rising Sun. Our campaign involved 16 telescopes in Asia, Europe, and North America. We observed BL Lacertae and CGRaBS J0211+1051 for a combined 685 telescope hours. We find large variations in the polarization degree and angle for both sources on sub-hour timescales as well as a $ rotation of the polarization angle in CGRaBS J0211+1051 in less than two days. We compared our high-cadence observations to particle-in-cell magnetic reconnection and turbulent plasma simulations. We find that although the state-of-the-art simulation frameworks can produce a large fraction of the polarization properties, they do not account for the entirety of the observed polarization behavior in blazar jets.9 pagesen-USThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Public Domainhttps://creativecommons.org/publicdomain/mark/1.0/Text